Jump to content

Stockalike RF Engine Configs v3.2.6 [01/20/19][RF v12]


Recommended Posts

One exception are the NTR engines, which all are *really* underweight in stock, so those will be noticeably more massive.

Raptor, I've seen you mention this several times, but I'm curious- where exactly are you getting mass/TWR figures for the NTR's?

Are you using figures from the old, (comparatively) low-tech NERVA program, or are you using designs from the much more advanced Timberwind and BNTR (Bimodal Nuclear Thermal Rocket) programs?

The Russians also continue to work on NTR designs under a veil of semi-secrecy, from what I've heard. And NASA has an entire team dedicated just to keeping older designs up-to-date with newer materials and minor engineering refinements. So it probably wouldn't be unreasonable to assume even lower masses than the ones from Timberwind or the BNTR programs for the most modern NTR designs...

Regards,

Northstar

P.S. You may never have heard of Timberwind of the BNTR programs. The BNTR program, which also goes by other names, refers specifically to the US/Russian join-program in 1992-1993 referenced in this article and in one of the NASA Mars Design Reference Mission documents. Project Timberwind was a top-secret government program that was developed for the Star Wars program from 1987-1991 until it was shut down by an anti-nuclear whistleblower in 1992 (you may have even noticed me making snide remarks about said man, Steven Aftergood, and his overblown fears of nuclear rockets on certain threads on this forum...)

Edited by Northstar1989
Link to post
Share on other sites
Raptor, I've seen you mention this several times, but I'm curious- where exactly are you getting mass/TWR figures for the NTR's?

Are you using figures from the old, (comparatively) low-tech NERVA program, or are you using designs from the much more advanced Timberwind and BNTR (Bimodal Nuclear Thermal Rocket) programs?

The Russians also continue to work on NTR designs under a veil of semi-secrecy, from what I've heard. And NASA has an entire team dedicated just to keeping older designs up-to-date with newer materials and minor engineering refinements. So it probably wouldn't be unreasonable to assume even lower masses than the ones from Timberwind or the BNTR programs for the most modern NTR designs...

Regards,

Northstar

P.S. You may never have heard of Timberwind of the BNTR programs. The BNTR program, which also goes by other names, refers specifically to the US/Russian join-program in 1992-1993 referenced in this article and in one of the NASA Mars Design Reference Mission documents. Project Timberwind was a top-secret government program that was developed for the Star Wars program from 1987-1991 until it was shut down by an anti-nuclear whistleblower in 1992 (you may have even noticed me making snide remarks about said man, Steven Aftergood, and his overblown fears of nuclear rockets on certain threads on this forum...)

The original configs originated with me and through the use of tech level increases were intended to range from early NTR (assuming something similar to Kiwi had been a flight capable model) to Pewee 2 / NERVA. (in inspiration only, assuming a Kerbal program somewhat more ambitious than ours)

Unfortunately one of the RF updates broke things a bit and threw things askew.

The Trimodal is based on the Pratt & Whitney Triton proposal with tech updates. (survived the aforementioned RF update intact...)

Link to post
Share on other sites
Raptor, I've seen you mention this several times, but I'm curious- where exactly are you getting mass/TWR figures for the NTR's?

From people like Starwaster and NathanKell. I tend to assume these guys have researched their stuff, so I save myself the time and work on the config wrangling. Depending on tech level, I believe you get TWRs from somewhere around 1.5 up through around 10 for the NTR engines. Or, at least that's what the spreadsheet gives as the goal.

The original configs originated with me and through the use of tech level increases were intended to range from early NTR (assuming something similar to Kiwi had been a flight capable model) to Pewee 2 / NERVA. (in inspiration only, assuming a Kerbal program somewhat more ambitious than ours)

Unfortunately one of the RF updates broke things a bit and threw things askew.

The Trimodal is based on the Pratt & Whitney Triton proposal with tech updates. (survived the aforementioned RF update intact...)

The trimodal NTR is the one you posted a while back on this thread. The regular NTR should be close to the spreadsheet goals. Starts with TWR of 1.4 at TL 3. I don't know what the mass ends up at for the highest TL, but given the curve the TWR should be around 9 or just under. Thrust is 60 kN. Seems about right when comparing to Atomic Rockets' stats.

Also, the new "webapp" system that I've been working on is about done. I'm hoping to start using that sometime this week, maybe this weekend. Should make adding engines quite easy for anyone, and maybe help out with updates on the repo. It'll also be a place where everyone can see configs and see the stats without having to dig through a 30,000-line file. With this, I'm planning to break up the config into multiple files (probably by mod) for easier reading and updating.

Link to post
Share on other sites

Ok all. I've finished the webapp enough to post it here. There are a few minor details that need to be fixed still, but it's mostly ready. Check it out here: http://bit.ly/rfstockalike

Basically, you'll be able to see the stats that go into making any engine, and tweak them if you want to use a custom config. Also, if you have an engine that isn't part of the main config, there's a blank template for you to use and it will give you a config to copy into your own MM files. Perfect for pull requests too (hint, hint). :)

Let me know if this is useful for you all.

Link to post
Share on other sites
From people like Starwaster and NathanKell. I tend to assume these guys have researched their stuff, so I save myself the time and work on the config wrangling. Depending on tech level, I believe you get TWRs from somewhere around 1.5 up through around 10 for the NTR engines. Or, at least that's what the spreadsheet gives as the goal.

Interesting. But the TWR of later-generation NTR's reached as high as *30*, with much higher total thrust than NERVA as well. The Timberwind NTR designs, for instance, had the following design stats... (these were taken directly from the Wikipedia article)

Timberwind 45

Diameter: 13.94 ft (4.25 m)

Vacuum thrust: 99208 lbf (441.3 kN)

Sea level thrust: 88305 lbf (392.8 kN)

Vacuum specific impulse: 1000 s

Sea level specific impulse: 890 s

Engine mass: 3300 lb (1500 kg)

Thrust to Weight Ratio: 30

Burn time: 449 s

Propellants: Nuclear/LH2

Timberwind 75

Diameter: 5.67 ft (2.03 m)

Vacuum thrust: 165347 lbf (735.5 kN)

Sea level thrust: 147160 lbf (654.6 kN)

Vacuum specific impulse: 1000 s

Sea level specific impulse: 890 s

Engine mass: 5500 lb (2500 kg)

Thrust to Weight Ratio: 30

Burn time: 357 s

Propellants: Nuclear/LH2

Timberwind 250

Diameter: 8.70 m (28.50 ft).

Vacuum thrust: 2,451.6 kN (551,142 lbf).

Sea level thrust: 1,912.300 kN (429,902 lbf)

Vacuum specific impulse: 1,000 s.

Sea level specific impulse: 780 s.

Engine mass: 8,300 kg (18,200 lb).

Thrust to Weight Ratio: 30

Burn time: 493 s

Propellants: Nuclear/LH2

Even higher engine TWR's could have theoretically been achieved by replacing the LH2 with Methane...

Regards,

Northstar

Edited by Northstar1989
Link to post
Share on other sites
Interesting. But the TWR of later-generation NTR's reached as high as *30*, with much higher total thrust than NERVA as well. The Timberwind NTR designs, for instance, had the following design stats... (these were taken directly from the Wikipedia article)

Timberwind was a very different technology. Particle bed instead of solid core. It also lacked the testing that previous nuclear rocket designs had being a theoretical design. No actual models existed. There is for instance no Timberwind equivalent even of Kiwi.

You can't really refer to Timberwind as being a 'later generation NTR' since it existed primarily on paper.

I concentrated primarily on translating something into the game that had actual hardware behind it even if we're still lacking actual flight capable product.

Link to post
Share on other sites

Once we get into stuff we haven't even flown (much less ground tested) I'm really hesitant to make any kind of assumptions. I'm not the smartest person in the room when it comes to that. Much beyond the LANTR I'd say that's in NearFuture territory or something. Besides, there's really nothing out there representing a pebble bed NTR. Porkjet just came out with a LANTR (which we have in the trimodal LV-N) and a gas core NTR (link: http://forum.kerbalspaceprogram.com/threads/104855-0-90-Atomic-Age-Nuclear-Rockets), but that's as close as we get.

I did read the Wiki article and saw the stats on Timberwind (which appears to be where the stats posted come from) so don't think I'm ignoring it. But, A) I can't get around RealFuels' code which specifies certain mass reductions with tech level for specific types of engines (which is roughly modeled within the spreadsheets I've used), and B) if I can't come up with a curve/function to model these things, it's not happening. I just don't have the time to research and write individual, one-off configs for every engine that was dreamed up by NASA, Roscosmos, SpaceX, ESA, or whomever.

If you want to play with configs, you can mess around with the new app I posted and pull up the blank template engine. It'll give you a good idea of what changes what in the config, in real time. Copy the result config and paste into a MM config file and see how she flies.

Speaking of tech levels, I was wondering about adjusting the tech tree node you get an engine in to be tied to the initial tech level. So, for a TL 2 engine, the config would make the techRequired = advRocketry. It's just a bit odd to me that the only advancement the game seems to have is to make engines bigger. Not sure of how much I want to bump into RP-0 or RealismOverhaul, but it'd be nice to have a 2.5m engine or a 3.75m engine in the lower nodes. Thoughts?

Link to post
Share on other sites

Raptor831,

The webapp looks great. I attempted to use it to create a config for the Atomic Age engines but couldn't get it to work (Maybe i'll try some easier engines tomorrow:)). I did get a config to work for the Lightbulb engine using the spreadsheet.

Webapp:

@PART[nuclearEngineLightbulb]:FOR[RealFuels_StockEngines] //CCGC-7 Nuclear Lightbulb
{

@mass = 20
@cost = 396345
%entryCost = 1981725
@maxTemp = 2400


@MODULE[ModuleEnginesFX]
{
@maxThrust = 450
@heatProduction = 1,682
@atmosphereCurve
{
@key,0 = 0 1,440
@key,1 = 1 644
}
!PROPELLANT[LiquidFuel] {}
!PROPELLANT[Oxidizer] {}
!PROPELLANT[MonoPropellant] {}
PROPELLANT
{
name = LqdHydrogen
ratio = 100.000000
DrawGauge = True
}

}

MODULE
{
name = ModuleEngineConfigs
type = ModuleEnginesFX
techLevel = 7
origTechLevel = 7
engineType = N
origMass = 20
configuration = NTRLqdHydrogen
modded = false

CONFIG
{
name = NTRLqdHydrogen
maxThrust = 450
heatProduction = 1,682
PROPELLANT
{
name = LqdHydrogen
ratio = 100
DrawGauge = True
}

IspSL = 1.5000
IspV = 1.5000
throttle = 0
MODULE
{
name = ModuleEngineIgnitor
ignitionsAvailable =
autoIgnitionTemperature = 800
ignitorType = Electric
useUllageSimulation = true
IGNITOR_RESOURCE
{
name = ElectricCharge
amount = 4.5
}
}

}
}
!MODULE[ModuleEngineIgnitor] {}
MODULE
{
name = ModuleEngineIgnitor
ignitionsAvailable =
autoIgnitionTemperature = 800
ignitorType = Electric
useUllageSimulation = true
IGNITOR_RESOURCE
{
name = ElectricCharge
amount = 4.5
}
}

!MODULE[ModuleAlternator] {}
!MODULE[ModuleGenerator] {}
!RESOURCE[U235Rods] {}
!RESOURCE[DepU235Rods] {}
MODULE
{
name = ModuleAlternator
OUTPUT_RESOURCE
{
name = U235Rods
rate = -37.5E-18
}
OUTPUT_RESOURCE
{
name = DepU235Rods
rate = 37.5E-18
}
OUTPUT_RESOURCE
{
name = ElectricCharge
rate = 22.5
}
}
MODULE
{
name = ModuleGenerator
isAlwaysActive = true
OUTPUT_RESOURCE
{
name = ElectricCharge
rate = 11.25
}
OUTPUT_RESOURCE
{
name = DepU235Rods
rate = 37.5E-18
}
INPUT_RESOURCE
{
name = U235Rods
rate = 37.5E-18
}
}
RESOURCE
{
name = U235Rods
amount = 37.5
maxAmount = 37.5
}
RESOURCE
{
name = DepU235Rods
amount = 0
maxAmount = 37.5
}

}

Spreadsheet:

    @PART[nuclearEngineLightbulb]:FOR[RealFuels_StockEngines] //CCGC-7 Nuclear Lightbulb
{
@mass = 20
@cost = 790002
@maxTemp = 13868

@MODULE[ModuleEnginesFX]
{
@maxThrust = 450
@heatProduction = 1671
@atmosphereCurve
{
@key,0 = 0 1440
@key,1 = 1 644
}
!PROPELLANT[LiquidFuel] {}
!PROPELLANT[Oxidizer] {}
!PROPELLANT[MonoPropellant] {}
PROPELLANT
{
name = LqdHydrogen
ratio = 100
DrawGauge = True
}
}

MODULE
{
name = ModuleEngineConfigs
type = ModuleEnginesFX
techLevel = 7
origTechLevel = 7
engineType = N
origMass = 20
configuration = LqdHydrogen
modded = false
CONFIG
{
name = LqdHydrogen
maxThrust = 450
heatProduction = 1671

PROPELLANT
{
name = LqdHydrogen
ratio = 1
DrawGauge = True
}
PROPELLANT
{
name = U235Rods
ratio = 0.00000000001
}
IspSL = 1.5
IspV = 1.5
throttle = 0

ModuleEngineIgnitor
{
name = ModuleEngineIgnitor
ignitionsAvailable = 1
autoIgnitionTemperature = 800
ignitorType = Electric
useUllageSimulation = true
IGNITOR_RESOURCE
{
name = ElectricCharge
amount = 4.5
}
}
}

}
!MODULE[ModuleEngineIgnitor] {}
MODULE
{
name = ModuleEngineIgnitor
ignitionsAvailable = 1
autoIgnitionTemperature = 800
ignitorType = Electric
useUllageSimulation = true
IGNITOR_RESOURCE
{
name = ElectricCharge
amount = 4.5
}
}
!MODULE[ModuleAlternator] {}
!MODULE[ModuleGenerator] {}
!RESOURCE[U235Rods] {}
!RESOURCE[DepU235Rods] {}
MODULE
{
name = ModuleAlternator
OUTPUT_RESOURCE
{
name = U235Rods
rate = -3.75E-017
}
OUTPUT_RESOURCE
{
name = DepU235Rods
rate = 3.75E-017
}
OUTPUT_RESOURCE
{
name = ElectricCharge
rate = 22.5
}
}
MODULE
{
name = ModuleGenerator
isAlwaysActive = true
OUTPUT_RESOURCE
{
name = ElectricCharge
rate = 11.25
}
OUTPUT_RESOURCE
{
name = DepU235Rods
rate = 3.75E-017
}
INPUT_RESOURCE
{
name = U235Rods
rate = 3.75E-017
}
}
RESOURCE
{
name = U235Rods
amount = 37.5
maxAmount = 37.5
}
RESOURCE
{
name = DepU235Rods
amount = 0
maxAmount = 37.5
}
} @MODULE[ModuleEnginesFX]
{
@maxThrust = 450
@heatProduction = 1671
@atmosphereCurve
{
@key,0 = 0 1440
@key,1 = 1 644
}
!PROPELLANT[LiquidFuel] {}
!PROPELLANT[Oxidizer] {}
!PROPELLANT[MonoPropellant] {}
PROPELLANT
{
name = LqdHydrogen
ratio = 100
DrawGauge = True
}
}

MODULE
{
name = ModuleEngineConfigs
type = ModuleEnginesFX
techLevel = 7
origTechLevel = 7
engineType = N
origMass = 20
configuration = LqdHydrogen
modded = false
CONFIG
{
name = LqdHydrogen
maxThrust = 450
heatProduction = 1671

PROPELLANT
{
name = LqdHydrogen
ratio = 1
DrawGauge = True
}
PROPELLANT
{
name = U235Rods
ratio = 0.00000000001
}
IspSL = 1.5
IspV = 1.5
throttle = 0

ModuleEngineIgnitor
{
name = ModuleEngineIgnitor
ignitionsAvailable = 1
autoIgnitionTemperature = 800
ignitorType = Electric
useUllageSimulation = true
IGNITOR_RESOURCE
{
name = ElectricCharge
amount = 4.5
}
}
}

} CONFIG
{
name = LqdHydrogen
maxThrust = 450
heatProduction = 1671

PROPELLANT
{
name = LqdHydrogen
ratio = 1
DrawGauge = True
}
PROPELLANT
{
name = U235Rods
ratio = 0.00000000001
}
IspSL = 1.5
IspV = 1.5
throttle = 0

ModuleEngineIgnitor
{
name = ModuleEngineIgnitor
ignitionsAvailable = 1
autoIgnitionTemperature = 800
ignitorType = Electric
useUllageSimulation = true
IGNITOR_RESOURCE
{
name = ElectricCharge
amount = 4.5
}
}
}


I'm not sure what the issue was, but I did notice the webapp version didn't have the U235 rods as a propellant. I'm not sure if that matters since the generator is always on. Would a NTR reactor (with a generator that is always at 100%) always be "full power" or is it throttled when not thrusting?

I just tested the LV-N and it doesn't seem to provide any electric charge, even when using action groups to toggle the generator. That might be a Real Fuels bug.:(

Link to post
Share on other sites
Timberwind was a very different technology. Particle bed instead of solid core. It also lacked the testing that previous nuclear rocket designs had being a theoretical design. No actual models existed. There is for instance no Timberwind equivalent even of Kiwi.

You can't really refer to Timberwind as being a 'later generation NTR' since it existed primarily on paper.

I concentrated primarily on translating something into the game that had actual hardware behind it even if we're still lacking actual flight capable product.

There was nothing impossible to accomplish about the Timberwind design. It was on-schedule for testing only a short time after when it was cancelled. The *ONLY* reason it was never built was due to the secrecy of the program being compromised and public/congressional outcry against the use of a nuclear rocket. Oh yeah, and budget concerns- can't forget those (basically any major new rocket technology project has been cancelled due to budget-concerns by Congress, which cares 100 times more about developing nuclear weapons than developing nuclear rockets...)

Also, on an ENTIRELY DIFFERENT note, I've found evidence that you probably should have never rolled back the reductions to the thrust ratings of LH2/LOX engines compared to their hypergolic and Kero/LOX fuel-modes. See the following quote from this page on SSTO's:

"While kerosene tanks can be 1% of the weight of their contents, hydrogen tanks often must weigh 10% of their contents. This is because of both the low density and the additional insulation required to minimize boiloff (a problem which does not occur with kerosene and many other fuels). The low density of hydrogen further affects the design of the rest of the vehicle  pumps and pipework need to be much larger in order to pump the fuel to the engine. The end result is the thrust/weight ratio of hydrogen-fueled engines is 30–50% lower than comparable engines using denser fuels."

I *KNEW* Hydrolox engines are you currently had them implemented were too good to be true! All hail the one true king of REAL rocket engines- Kerosene! (at least until Meth/LOX starts seeing more serious development) :D

Regards,

Northstar

Edited by Northstar1989
Link to post
Share on other sites
There was nothing impossible to accomplish about the Timberwind design. It was on-schedule for testing only a short time after when it was cancelled. The *ONLY* reason it was never built was due to the secrecy of the program being compromised and public/congressional outcry against the use of a nuclear rocket. Oh yeah, and budget concerns- can't forget those (basically any major new rocket technology project has been cancelled due to budget-concerns by Congress, which cares 100 times more about developing nuclear weapons than developing nuclear rockets...)

Irrelevant. I make no claim as to viability. To clarify: I focused on actual hardware with real test data to back it up. Whether a theoretical design was or was not feasible was not a factor.

Also, on an ENTIRELY DIFFERENT note, I've found evidence that you probably should have never rolled back the reductions to the thrust ratings of LH2/LOX engines compared to their hypergolic and Kero/LOX fuel-modes. See the following quote from this page on SSTO's:

"While kerosene tanks can be 1% of the weight of their contents, hydrogen tanks often must weigh 10% of their contents. This is because of both the low density and the additional insulation required to minimize boiloff (a problem which does not occur with kerosene and many other fuels). The low density of hydrogen further affects the design of the rest of the vehicle  pumps and pipework need to be much larger in order to pump the fuel to the engine. The end result is the thrust/weight ratio of hydrogen-fueled engines is 30–50% lower than comparable engines using denser fuels."

Are you sure that should be directed to me? What hydrolox? Unless you're talking about the LANTR (trimodal) changes then I had nothing to do with any rollbacks. And nothing you're posting above is relevant to that. (if it matters, those changes were made because the LANTR config was expending too much H2 in H2/O2 mode)

Link to post
Share on other sites

Currently, many (all?) of the liquid engines have the same thrust for hydrolox, kerolox, and hypergolic configurations. This probably makes hydrolox the best choice unless you are very limited by volume, like early in career mode.

I think setting up a new NTR also defaults to the same thrust for hydrogen, methane, and ammonia, which would make hydrogen the obvious choice if you can limit the boiloff with heat pumps.

Link to post
Share on other sites
Raptor831,

The webapp looks great. I attempted to use it to create a config for the Atomic Age engines but couldn't get it to work (Maybe i'll try some easier engines tomorrow:)). I did get a config to work for the Lightbulb engine using the spreadsheet.

..snip..

I'm not sure what the issue was, but I did notice the webapp version didn't have the U235 rods as a propellant. I'm not sure if that matters since the generator is always on. Would a NTR reactor (with a generator that is always at 100%) always be "full power" or is it throttled when not thrusting?

I just tested the LV-N and it doesn't seem to provide any electric charge, even when using action groups to toggle the generator. That might be a Real Fuels bug.:(

Ah, phooey. The app is formatting the numbers to have commas, which will probably break the config. Fixable. And the NTRs should have U235Rods as a PROPELLANT. Fixable. Thanks for reporting on that.

@Northstar1989: I'd been debating adding the hydrolox thrust nerf back in. NathanKell's spreadsheet dropped that particular thing, and I figured there was a good reason why, so I didn't mess with it at the time. But, I really think that'd be better with the nerf. And, it's much easier now with the webapp for myself to make that change! :wink:

Link to post
Share on other sites

OK, I've updated the webapp to fix the errors lurkaholic found, and to include the varying thrust for differing fuel mixtures. So, if you have an engine that uses hydrolox and kerolox, when using the hydrolox variant you'll get less thrust. Hopefully, this should make the webapp give the same configs (with a few calc tweaks) as the spreadsheet does. If you test any webapp configs, let me know.

Link to post
Share on other sites
I need help. Tantares tanks won't let me change their fuel types. Is there a fix for this?

This config doesn't add RF capabilities to any tanks. I have the Tantares engines added, true, but they both need configs for it to work. Adding those are pretty easy though. Here's a quick-and-dirty way to do it: http://forum.kerbalspaceprogram.com/threads/81239-Stockalike-RF-Engine-Configs-v2-0-6-11-26-14?p=1237946&viewfull=1#post1237946 As NathanKell has pointed out a few times, we really should be figuring out the volume of the part and then multiplying that by a usability factor (i.e. pill-shaped tanks inside of a cylinder can't use the entire volume). But, the linked way works and is usually close enough.

If you do make the tank configs, consider making a pull request on the Real Fuels repo as well, so everyone can have the tanks set up.

Link to post
Share on other sites
This config doesn't add RF capabilities to any tanks. I have the Tantares engines added, true, but they both need configs for it to work. Adding those are pretty easy though. Here's a quick-and-dirty way to do it: http://forum.kerbalspaceprogram.com/threads/81239-Stockalike-RF-Engine-Configs-v2-0-6-11-26-14?p=1237946&viewfull=1#post1237946 As NathanKell has pointed out a few times, we really should be figuring out the volume of the part and then multiplying that by a usability factor (i.e. pill-shaped tanks inside of a cylinder can't use the entire volume). But, the linked way works and is usually close enough.

If you do make the tank configs, consider making a pull request on the Real Fuels repo as well, so everyone can have the tanks set up.

Thanks for that! I'll try to make some configs. By the way, how about if there's LF+O and Monopropellant? Will I also add in monopropellant * 5?

Link to post
Share on other sites

I also had this line "ignitionsAvailable = " in my config. Adding a 0 or 1 to the end allowed it to work. I'm not sure how long I spent comparing two files before I found that. :blush:

Raptor831, When configuring a NTRLqdMethane engine, it adds TEATEB as a propellant.

Link to post
Share on other sites

Hi, is there any place you can read up on the parameters of engine configs?

More specifically I have trouble understanding how you can define all three of Isp, thrust and fuel consumption (maybe I do not understand the function of the "ratio" parameter correctly?)

at once, since for each two being defined, the third would be strictly set by my understanding...

Thanks for any help in advance!

Link to post
Share on other sites
Hi, is there any place you can read up on the parameters of engine configs?

More specifically I have trouble understanding how you can define all three of Isp, thrust and fuel consumption (maybe I do not understand the function of the "ratio" parameter correctly?)

at once, since for each two being defined, the third would be strictly set by my understanding...

Thanks for any help in advance!

You are correct that the Isp and thrust would determine the mass flow rate out of the engine. The mass ratio setting is used to set the fuel/oxidizer mixture. The output for the config will be the volume ratio since the units ingame are liters. The mass ratio isn't used for monopropellant engines (e.g. hydrazine only engine or a standard Nuclear Thermal engine).

The third post on the real fuels thread and the "Calcs_RF_Stockalike.xls" spreadsheet on Raptor831's github page both have information on engine configurations.

Edited by lurkoholic
Link to post
Share on other sites

Ah, well that makes significantly more sense. I initially thought that as well, but the cfg documentation for ModuleEngines said "Not to be confused with ratio relative to other propellants." regarding the ratio parameter... Thanks for clearing that up!

So ratio is basically just the percentage of each fuel being used and the actually fuel consumption in liters/s gets calculated by the game? Nice.

Link to post
Share on other sites
Hi, is there any place you can read up on the parameters of engine configs?

More specifically I have trouble understanding how you can define all three of Isp, thrust and fuel consumption (maybe I do not understand the function of the "ratio" parameter correctly?)

at once, since for each two being defined, the third would be strictly set by my understanding...

Thanks for any help in advance!

lurkaholic is correct. In addition to that, I'm hoping to get the instructions from the XLS on the webapp as soon as I can. All of those options are very confusing, so some form of explanation needs to be there somewhere.

I noticed that Aerojet Kerbodyne's ICPS engine is not working. It shows two engine configs when I right click on it. (Hydrolox and Monopropellant mixtures) It appears the game is reading it both as an engine, and an rcs thruster.

I haven't updated the Aerojet Kerbodyne engines in a while, but are there both RCS ports and an engine in that part? If so, then it should be working as advertised. They'd both be different "engines" in the eyes of the game. If not, well, then it's obvious we have a bug! :)

EDIT:

I also had this line "ignitionsAvailable = " in my config. Adding a 0 or 1 to the end allowed it to work. I'm not sure how long I spent comparing two files before I found that. :blush:

Raptor831, When configuring a NTRLqdMethane engine, it adds TEATEB as a propellant.

Did the "ignitionsAvailable = " come from the webapp? If so, can you repeat how you got it? I tried quickly, but I couldn't reproduce.

Second, the TEATEB on the NTRs should no longer be an issue. Thanks again for the find.

Edited by Raptor831
Link to post
Share on other sites
Did the "ignitionsAvailable = " come from the webapp? If so, can you repeat how you got it? I tried quickly, but I couldn't reproduce.

Start a new blank engine and select Nitrogen or any of the propellants below it. It leaves "ignitionsAvailable= " blank until you enter a number on the EI ignitions or click Use Default Ignitions.

If it matters, it will also still put a comma in the heat production field.

Link to post
Share on other sites

I haven't updated the Aerojet Kerbodyne engines in a while, but are there both RCS ports and an engine in that part? If so, then it should be working as advertised. They'd both be different "engines" in the eyes of the game. If not, well, then it's obvious we have a bug! :)

It's just one engine so it's a bug. Anyways, I tried to put The two different mixtures in the separate tanks and it worked! :D

Link to post
Share on other sites
Start a new blank engine and select Nitrogen or any of the propellants below it. It leaves "ignitionsAvailable= " blank until you enter a number on the EI ignitions or click Use Default Ignitions.

If it matters, it will also still put a comma in the heat production field.

It's just one engine so it's a bug. Anyways, I tried to put The two different mixtures in the separate tanks and it worked! :D

Thanks to you both for checking into these things. I'll see if I can get that taken care of ASAP.

Link to post
Share on other sites
This thread is quite old. Please consider starting a new thread rather than reviving this one.

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...